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Why the need for so much torque ?

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Not saying it's wrong, I just think it's overkill.

 

It all depends on the application. Most simracers do not want to drive with 1:1 forces. Personally I'm not an athlete, nor am I training to drive a real race car, so I would be happy with a wheel which offers a maximum of 10Nm of torque.

 

Now take somebody who wants to train for real life racing. F3 and GP2 cars (both high downforce cars) require forces of up to 30Nm when cornering, with the driver sitting in a relatively tight environment. If you want to physically train for those situations, you will require a Bodnar or OSW.

 

Since we actually build turn-key simulators for race teams, we work with these high-end systems. Would we advise the majority of simracers to buy a Bodnar with 26Nm of torque? Probably not.

 

It's the same for our pedal sets. We offer both the Pro (55kg max. brake force) and Ultimate (135kg max. brake force) pedals. The Ultimate pedals can offer you 1:1 forces compared to real formula cars. Yet 90% of simracers will be perfectly happy with the Pro pedals.

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Now take somebody who wants to train for real life racing. F3 and GP2 cars (both high downforce cars) require forces of up to 30Nm when cornering, with the driver sitting in a relatively tight environment. If you want to physically train for those situations, you will require a Bodnar or OSW.

Right! Exactly what I was trying to say above. Training tool requires the high torque.

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I think the massive torque in the OSW just gives me a reason to skip "upper body day" at the Gym (pronounced "gime" of course)...

 

...Nah that was just a lie. I don't go to the gime anymore. I stopped going right around the same time was getting into iRacing...wonder if there's a correlation there. :-P :-P :-P

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I think you can get with a G27 as well. monotonous work is never good if you do it to much. Worst I got so far is tendencies for a tennis elbow.

True, it would never occur to me but I was reading a book on sim racing today and the author brought this up as a serious risk with newer, high power wheels. 

 

Guess with a proper moderation of seat time that shouldn't be a problem, just something to keep an eye on when going overboard with power.

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In real racing, the steering torque could be way beyond 45 Nm, huge dynamic range!

Sim SW today, rF2, iRacing, AC, etc do ouput hiigh dynamic range FFB too. The data fresh rate is pretty high at 100Hz (10ms interval).

Of course, one cannot handle on holding-torque at that high, but it is the transient torque matter. If you look at the telemetry data, the FFB is very sparking with huge variation at short burst. Consummer level sim wheel just will not be able to produce such high transient torque. You need high power Servo motor to do so.

The big MiGg motor used in OSW, has very fast response, it took about 3ms to ramp up to the given torque:

http://isiforums.net/f/attachment.php?attachmentid=16905&d=1433513336

 

such motor can be used to produce very realistic feel on FFB, with huge transient torque burst. I own several other wheel, none of them feel realistic. The Servo motor is the saviour in this regard.

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In real racing, the steering torque could be way beyond 45 Nm, huge dynamic range!

Sim SW today, rF2, iRacing, AC, etc do ouput hiigh dynamic range FFB too. The data fresh rate is pretty high at 100Hz (10ms interval).

Of course, one cannot handle on holding-torque at that high, but it is the transient torque matter. If you look at the telemetry data, the FFB is very sparking with huge variation at short burst. Consummer level sim wheel just will not be able to produce such high transient torque. You need high power Servo motor to do so.

The big MiGg motor used in OSW, has very fast response, it took about 3ms to ramp up to the given torque:

http://isiforums.net/f/attachment.php?attachmentid=16905&d=1433513336

 

such motor can be used to produce very realistic feel on FFB, with huge transient torque burst. I own several other wheel, none of them feel realistic. The Servo motor is the saviour in this regard.

 

Just for the record, AC FFB refresh rate is 333Hz. 

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David Tucker has commented on iRacing forums about the above. iRacing runs their physics engine at 360Hz and the main loop at 60Hz. The optimal would be 120Hz but for the time being PC's dont have the computing power to run iRacing at 120Hz considering all the parameters they handle during a racing session.

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rf2 runs 100Hz refresh rate (10ms), the FFB data are very sparking in F1 cars I ran. The transient FFB is 2x or 3x over the mean. On a sharp turn say, if holding-torque is 10 Nm, then transient torque burst could be over 20 or 30 Nm. This is very short burst, of course one may not feel that strong but it does give inner details. My AF wheel lacks of that inner details. I suspect the stepper motor might not have such resolution to response such transient torque.

Certainly, the a Servo motor will (ramp time <3ms):

 

http://isiforums.net/f/attachment.php?attachmentid=16905&d=1433513336

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David Tucker has commented on iRacing forums about the above. iRacing runs their physics engine at 360Hz and the main loop at 60Hz. The optimal would be 120Hz but for the time being PC's dont have the computing power to run iRacing at 120Hz considering all the parameters they handle during a racing session.

If you disable vsync, then you should go as far as your hardware can take you, 120ps or more...

 

This post has more info on this topic:

http://steamcommunity.com/app/241560/discussions/0/34096318669939263/

 

Higher FPS are also needed in VR, however there is a lot to do in 8.3 ms (120fps).

To get there probably easiest thing to do now is to get i5 or i7 cocked > 4.5 ghz and hope that iracing  will improve SLI or crossfire support.

 

When in doubt, use brute force :)

Long-term iracing should improve their engine (multi threaded rendering, sli/cf support, dx 11, 12, etc.).

 

In real racing, one of the rules is that more power is better, and I think it applies also the simulator wheel market.

Looking back where PC wheels started, I think there's been a lot of progress.

Unlike the flight sim market where FF joysticks died out, racing sim wheels are constantly getting better (bigger) and more sophisticated motors which improve the whole experience.

 

Unfortunately the best wheels are still a bit pricey (more than some used car) so I'm hoping that the we will see at some point mass market servo wheels and much improved drivers and game support.

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This is not frames per second, this has to do with the actual code base. Processing of the physics not video card throughput.

If I understand what you are trying to say, even  if you have 2X faster CPU and GPU, iracing will still run the main loop (and the rendering loop?) at 60 FPS?

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As far as I know, most sims out there output refresh rate via USB is <120 Hz. For rF2, it is 100Hz. For iRacing, sebj mentioned is 60Hz.

there are over 100 sets of physics data (so-call realtime "telemetry data), such as FFB data in this case, that got to send out every 10ms (100Hz).

You need a servo motor has response time far less than 10ms in order to get transient torque (realistic feel). I doubt the stepper motor is good enough.

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depends on what contexts  of your updates. If you want send a Ping message, then you surely have very high rate to go.

If you want sent a 1080P video, that is huge, so 120Hz or 60Hz likely. You can go higher, but will be costly...

For Physics data updates, that are huge too. Each physics data point, say FFB, is a "mesage", though. You have thousands of them need to update in real-time, then API inferface will limit its update rate. The core eng can update physics data at much higher rate but not at API.

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Well, if the engine is single threaded then it would probably be a good idea to look intro multithreading (or even fibers) for the engine overhaul.

Also compute shaders are a very good way do a lot of parallel physics calculations.

This should help with latency and faster framerates...

 

About API interface limit, probably best to talk to OS and peripherals folks who are maintaining it.

 

Although, wheel can only go left or right (+ some buttons :) so I don't see how the api would be the limiting factor?

What is the size of each physics update package?

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PC cannot handle true real-time non-linear modeling upates in general, ike the tire model, etc.

What most of PC sim out there is using "pre-calculated" results in most cases they can think of, then index to the tables. so, the updates are basically table look-up. Again output all the real-time results each every 10ms (100Hz) still amazing though.

 

I recalled on youtube there is a F1 simulator (reported by Fifth Gear) used 10 PCs costs about $400k.

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Joe you made an interesting comment so I posed that as a question on the iRacing forums. David Tucker, one of the staff, replied and said 

 

"No lookup tables at all, as far as I know. We don't even work on the usual tire curves. Dave is actually modelling the molecular bond of the rubber and everything."

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Interesting...

I know rF2 does.  I guess there is no fee lunch. Faster and simpler approach may trade off the physics, though. If eveyting is truely calcuated in real-time, you can imagine how much of those non-linear euqutions need to be simplified or with very rough approach in order to solve.

Here is example I found that rF2 suspension is far more realistic than AC:

 

http://isiforums.net/f/showthread.php/26211-Does-rF2-implement-chassis-flex-or-semi-chassis-flex/page2

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